Computer security is a serious concern in today's technology-driven culture. A breach of a computer's security can occur when the computer is infected with viruses and other forms of malicious software (malware). Such infections can occur, for example, when files (e.g., email) infected with malware are downloaded and opened, or infections may occur when malware accesses a computer over a network without any direct user intervention. In any case, the prevalence of these security threats has resulted in a wide variety of security-related tools that are available for computers. Examples of these tools include antivirus programs, adware scanners, firewalls, and the like. Despite the availability of these tools, computers continue to be infected with malware.
One reason for the persistence of malware infection is the ability of some malware to hide from security tools. Malware can hide from many security tools through the use of a rootkit, which generally stated, is a set of software tools intended to conceal running processes, files or system data from a computer's operating system. Rootkits can hook themselves very low in a computer's system (e.g., at the kernel level) and intercept the principal system services that the computer's operating system and other applications utilize while running on the computer. In one example, an antivirus tool that resides on a computer scans the computer's hard disk for viruses. As part of the scan process, the computer's operating system makes one or more function calls, such as an “open file” call for a certain file. However, malware that is resident on the computer may use a rootkit to intercept the “open file” function call and return a “file missing” error or return the wrong file. Thus, the antivirus tool is unable to access the requested file and check it for virus infection. If the requested file is infected with a virus, the infection will persist undetected.